How to make a rigid body system a static mesh?
After you have run your rigid body simulation, you have to options for how to apply the sim to the mesh.

Your first option is to simply apply the visual transform of the object(s).
Move to the frame where the object is at the location you want to keep, then select the rigid body object and press CtrlA > "Visual Transform".

Your other option is to bake the rigid body simulation to key frames.
Select the rigid body object, then press the "Bake To Keyframes" button in the physics tab of the tool shelf. Set the range of frames you want, leave the "Frame Step" at 1, then press the OK button.